Frozen fish package

ABSTRACT

A PACKAGING FOLDER FORMED FROM A FIBROUS BOARD HAVING A POROSITY IN THE RANGE OF 300 TO 650 SECONDS MEASURED ON A GURLEY DENSOMETER AND COATED ON ONE SURFACE WITH A RELEASE COATING PERMEABLE TO AIR BUT SUBSTANTIALLY PREVENTING PENETRATION OF WATER INTO THE BOARD AND PREFERABLY COATED ON THE OTHER SURFACE WITH A WAX COATING IMPERVIOUS TO WATER AND WATER VAPOUR.

p 1972 A. MCINTOSH VESSIE 3,690,923

FROZEN FISH PACKAGE 2 Sheets-Sheet 1 Filed Feb. 12, 1970 FIG.

IN VE'VTOR Alexander McINTOSH VESSIE Sept. 12, 1972 A. MOINTOSH VESSIEFROZEN FISH PACKAGE 2 Sheets-Sheet 2 Filed Feb. 12, 1970 INVENTORAlexander MclNTOSH VESSIE 3,690,923 FROZEN FISH PACKAGE AlexanderMcIntosh Vessie, Lachute, Quebec, Canada,

8SSlgll0l t0 The Price Company Limited, Quebec, Quebec, Canada FiledFeb. 12, 1970, Ser. No. 10,890 Int. Cl. Bc 9/04; C09d 5/00 Us. Cl.111-68 9 Claims ABSTRACT OF THE DISCLOSURE A packaging folder formedfrom a fibrous board having a porosity in the range of 300 to 650seconds measured on a Gurley densometer and coated on one surface with arelease coating permeable to air but substantially preventingpenetration of water into the board and preferably coated on the othersurface with a wax coating impervious to water and water vapour.

- FIELD OF THE INVENTION The present invention relates to material forpackaging. More specifically, the present invention relates to materialfor packaging frozen foods under pressure while permitting the escape ofair and substantially preventing adhesion of the product being packagedto the packaging material.

DESCRIPTION OF PRIOR ART There have been prior proposals to providepackaging material and packages specifically for frozen fish andWhereinair squeezed from the fish during the packaging operation ispermitted to escape through the material or package. One commerciallyacceptable material is a coated board having a plurality of spaceddepressions on its surface and into which the air from the fish issqueezed. While this type of board or package satisfactorily eliminatesthe air from the fish during freezer press compression, it has inherentdisadvantages particularly allowing the passage of moisture from theproduct during freezer I storage resulting in dehydration of theproduct.

SUMMARY OF INVENTION It is thus the object of the present invention toprovide an improved material for packaging compressed frozen foods.

Broadly, the present invention relates to a packaging board comprising afibrous board coated with a releasing agent to prevent sticking of thefrozen product to the v board. Theboard has a porosity in the range of300 to 650 seconds measured on the Gurley densometer. One surface of thefibrous board is treated with a release agent to coat the fibers thereofwhereby the surface remains permeable to air, but substantiallyimpermeable to water. Preferably, the board is highly sized and thesurface of the board facing the product to be packaged may be'sized to agreater degree than the remainder of the board. A moisture and waterimpervious wax coating is applied to the other surface of the board toact as a barrier to retain the moisturein the frozen fish in freezerstorage.

BRIEF DESCRIPTION OF DRAWINGS FIG. 3 is an isometric view of the web asit is being sheeted in the sheeter of FIG. 2;

3,690,923 Patented Sept. 12, 1972 FIG. 4 is an isometric view of the cutand creased blank after forming in the cutting and creasing station;

FIG. 5 is an isometric view of the blank as it is being folded in thefolding station; FIG. 6 is an isometric view of the folded and coatedblank delivered from the final coating station and coated on both sides.

DESCRIPTION OF PREFERRED EMBODIMENTS As illustrated in the drawings, theboard 10 is coated 1 on one side with a coating 12 that covers thesurface of the fibers adjacent the surface of the board, but leaves theinterstices between the fibers substantially free so that air maypenetrate into the board between adjacent fibers. The opposite surfaceof the board in the illustrated embodiment is provided with asubstantailly water vapour impervious barrier coating 14.

The board 10 may be cut and creased in any suitable manner to providethe required blank. However, when coating in accordance with one of thepreferred methods of the present invention, it is preferred to form theblank in a very specific manner as illustrated at 20 in FIG. 1. Thisblank 20 has the conventional cut lines represented by solid lines andcrease lines represented by dash lines and indicated at 16 and 18respectively. However, the two flaps 17 adjacent the back panel 19 arenot directly connected to the back panel as is normally the case butinstead are separated therefrom by lines of severance 21 and areconnected to side flaps 23 by crease lines 25.

The board 10 is preferably highly sized to provide the required degreeof wet strength commensurate with the amount of water vapour penetratingthe coating 12 with the air squeezed from the product being packaged andfrozen. Preferably, the size used is a rosin size and the degree ofsizing to at least a reading of about 30 grams per square meter for twominutes based on the Cobb test and preferably 26 to 24 grams per squaremeter. It has been found that this degree of sizing permits the board tomaintain the required degree of wet strength when coated as describedhereinbelow under conditions found in the packaging of frozen fish.

The porosity of the uncoated board 10 is of prime importance. This mustbe in the range of 300 to 650 seconds measured on the Gurley densometerand preferably will be in the range of 525 to 625 seconds. If thedensity is less than 300 seconds, it has been found to be substantiallyimpossible to prevent the product from sticking to the'board regardlessof the amount of coating applied, when using the specific coatingdescribed hereinbelow. When the density is above 650 seconds, the boardis not sufficiently porous to permit the required rate of penetration ofair into the board from the product being compressed and an inferiorail-pocketed product is produced. As indicated above, best results areobtained when the uncoated board has a porosity in the range of 525 to625 seconds measured on the Gurley densometer.

The thickness of the board should be at least .02 inches, i.e. aboveabout 20 point to provide the required strength characteristics toprovide the required space to absorb the air displaced from the materialbeing packaged and permit same to travel laterally and be dispensed atthe side edges of the .board. Thicker boards have a greater capacity toabsorb air and are better from that point of view, however, they aremore expensive and a balance is, therefore maintained to provide themost economical board for the specific purpose.

The board 10 is coated with a suitable release coating 12 to preventsticking of the product. It has been found that a silicone coating isvery satisfactory for this purpose. One suitable release coating and theone' preferred for the present invention contains a polysilozane andcatalyst and preferably also will contain a sizing agent. Thepolysilozane is an organic polysilozane sold under the registeredtrademark Syl-Oif by Dow Corning Corporation, Midland, Mich. Thisproduct contains organo-polysilozane and has a pH of 6.5 and a specificgravity at 77 F. of l. The catalyst is a metal organic salt sold underthe trade name EY142 also by Dow Corning. The preferred sizing agent isa zirconium-Wax complex sold under the registered trademark Sunsize FH"by Sun Chemical Corporation, 631 Central Ave., Carlstadt, NJ.

One specific coating incorporating a sizing agent is a water solutioncontaining about 15% by volume of Syl- Off 26, by volume of Sunsize and1% by volume of EY-142. This solution is used in the range of about 1 to3 pounds of silicone solids for three thousand square feet, preferablyabout 1.5 pounds of silicone solids for three thousand square feet witha board having a Cobb test reading of 24 to 26 grams per square meterfor two minutes and a porosity of 525 to 625 seconds on the Gurleydesometer before coating to provide a product having a Cobb test readingof 12 to grams per square meter and a porosity of 450 to 550 seconds onthe Gurley densometer after coating.

The coating 12 may be applied in any suitable manner, for example by aconventional roll type coater or the like wherein measured quantities ofcoating may be uniformly applied to the board. As above indicated, thepick-up will generally be about 1.5 pounds of silicone per threethousand square feet of board. After coating, the coated board is curedpreferably by passing same through an oven held at a temperature ofabove about 375 F. by means of infrared heaters and hot air. The lengthof the oven will depend on the temperature and speed of passage.However, complete curing of the silicone coating may not be necessary ifthe boards are wound into rolls and retain the heat whereby curing canbe completed during storage.

After the board has been coated, the porosity increases to bring theGurley densometer reading down to the range of 450 to 550 seconds. Inaddition, the Cobb test changes to 12 to 15 grams per square meter fortwo minutes due to the added size incorporated with the coating andconcentrated on the surface of the board facing the product. This addedsize is very important as it prevents moisture penetration into theboard and the formation of ice needles which would tend to bond theproduct being packaged to the board and prevent proper separation.

The sizing and release effect may be achieved by applying the size andrelease coating in several ways.

As indicated above, the release coating may be applied to a board sizedto a Cobb reading below about 30 grams per square meter and the releasecoating incorporate the further size required to reduce the Cobb readingto the range of 12 to 15 grams per square meter. Alternatively, theboard may be pre-sized to a lower reading on the Cobb test and less sizebe incorporated with the release coating. In some cases, the sizecontent of the release coating may be reduced to a minimum to facilitateapplication of the coating to the material. In any event, it ispreferred to have the resultant packaging board with a Cobb reading inthe range of 12 to 15 grams per square meter.

The impervious coating 14 is not a necessity but it will normally beapplied. Generally, some form of coating at least must be provided toprevent sticking of the package to the press platens. As abovedescribed, current folder packages permit a degree of escape of moisturefrom the frozen fish during freezer storage or transporation resultingin deterioration of fish quality.

To overcome this, folder packaged fish blocks are normally inserted intoimpervious polyethylene bags. The substantially impervious coating 14 ofwax or the like provides a seal which prevents escape of moisturethrough the board and thereby, in some cases, making the use ofpolyethylene bags unnecessary.

In operation, a blank may be formed from the board in the presentinvention and the material to be packaged placed into a container formedfrom said blank and pressed and frozen. Air pressed from the materialbeing packaged travels, as indicated by the arrows a and b, through thesurface of the board and then along the board and out at the side edges22 and 24 or end edges 26 and 28. In FIG. 1, these edges are shownspaced from the edge of the blank however, obviously, in operation, theedges will be the edges of the blank itself as indicated in FIG. 4. Theamount of air leaving the board at the edges 22, 24, 26 and 28 need notbe equal to the amount of air squeezed from the product being packagedif there is sufficient volume within the board itself to absorb this airwithout building up sufficient pressure to expel the air.

Referring to FIGS. 2 to 5 inclusive, the preferred method of coatingwill be described. The roll of board is unrolled and the web 102 fedthrough a coating station 104 wherein the release coating is applied andthen into and through an oven 106 wherein the release coating is cured.Next, the board is sheeted in sheeting station 108 and blanks 20 arethen formed from the sheet web by cutting and creasing in the cuttingand creasing station 110 and foldel along crease lines 105 and 25 (seeFIGS. 1 and 5) in the folding station 112 and finally the folded blankis coated on the outwardly exposed upward and downward facing surfacesof the folded blank in a second coating station 114 and are stacked instacker 116.

In the coating station 104 the web 102 is coated on its upper surface118 with a suitable coating 120. This coating is cured in the oven 106and the web is sheeted into individual sheets 122 (see FIG. 3) in thesheeting station 110.

The individual sheets 122 are then fed to the cutting and creasingstation 108 where the blank 20 is cut and creased as shown in FIGS. 1and 4.

After the blank has been formed, it is moved into a folding stationschematically indicated at 112 in FIG. 2 and is folded along the foldline 105 and its extensions 25 so that the inner surface 118 having thecoating is in face-to-face relationship with itself as shown in FIG. 6.After the blank 20 has been folded as described, it is ready for passagethrough the second coating station 114 where the outer coating isapplied to the outer exposed surfaces 124 of the blank.

The fold on crease line 105 and its extensions 25 forms the leading endof the blank as the blank moves through the coating station 114. Thisfold substantially prevents the penetration of coating material into theleading edge and onto the inner surface of the side flaps 23, therebyprotecting the inner previously coated surfaces 18 of the blank frombeing coated with coating applied in coating station 114.

A locking flap 126 extends from the bottom portion of the folded blankrearward of the edge 128 of the top portion. This locking flap is thusexposed on both surfaces as it traverses the coating station 114 and istherefore coated on both sides. Coating of the flap 126 on both sidestends to further rigidify same.

As indicated, the outer surfaces 124, which in effect is the bottomsurface of the Web 102 being withdrawn from the roll 100, is thuscompletely coated with a coating 128.

In some cases, it may be desirable to cut and score the web 102 prior tothe coating station 104 so that the release coating is applied only tothe blank 20, not to the material on the web surrounding the blank. Inthis case, a separate blanking station will precede the coating station104.

Modifications may be made without departing from the spirit of theinvention as defined in the appended claims.

I claim:

1. A packaging board comprising a sized fibrous board having an uncoatedporosity of 300-650 seconds measured on a Gurley densometer, one surfaceof said fibrous board being a surface treated with a release agent tocoat only the fibers thereof whereby said surface remains permeable toair through the interstices between fibers, and said surface is renderedsubstantially impermeable to water and the second surface of saidfibrous board being coated with a continuous film substantiallyimpermeable to both water and water vapour.

2. A board as defined in claim 1, wherein-said fibrous board has a goodwet strength to resist softening due to Water vapour penetrating theboard with air.

3. A board as defined in claim 2, wherein said uncoated fiber board hasone surface sized to a maximum reading of 30 grams per square meter fortwo minutes on the Cobb test before said one surface is treated withsaid release agent.

4. A board as defined in claim 3, wherein said one surface has a Cobbtest reading of 12-15 grams per square meter for two minutes aftertreatment with a release agent.

5. A board as defined in claim 4, wherein said release agent is asilicone polymer.

6. A board as defined in claim 5, wherein said release agent is anorgano polysiloxane.

7. A board as defined in claim 5, wherein said release agent contains asizing agent.

References Cited UNITED STATES PATENTS 2,920,979 1/ 1960 Hessburg et al.117-68 2,676,897 4/ 1954 Trillich 11768 3,050,411 8/1962 Keil 117-68.52,895,853 7/1959 Bailey 117-135.5 3,425,863 2/1969 Wadu et a1 1l7l35.53,336,158 8/1967 Honig et a1. 117-1355 ALFRED L. LEAVITT, PrimaryExaminer M. F. ESPOSITO, Assistant Examiner US. Cl. X.R.

1l7--685, 135.5, 161ZA,168

